I'm trying to optimize some code, and fighting for every byte as usual.
I've got 1070 bytes of code that's got to fit in 1024 bytes of memory - you
know the drill.  No, I can't buy more memory - it costs money.  Gotta
squeeze my code.


I'm replacing more and more C with assembler.  This is going the wrong way.

I've noticed that C always makes a less efficient loop than can be done with
hand coded assembler.
I need a loop that executes 256 times (handy number, eh?)


I'm comparing the assembly instructions:

int x;

#ASM
            // CLRF X is implied - I make sure X is always zero at this
point
label:
        { code code code code}
        decfsz x, f
        goto label
#ENDASM

which generates a nice tight loop which executes 256 (or is it 255? ) times
and uses 2 bytes of overhead for the loop.

Racing them against ANY of the looping instructions in C -  such as

for (X = 0; x < 256; x++)
{ code code code}


for(x = 255; x > 0; x--)
{code code code code}

while (x > 0)
{ code code code code
    x--
}

which can generate a loop in AT BEST 5 and usually 6 0r 7 bytes.


Is there a C instruction that can make a nice tight loop that takes up 2
bytes of ROM and executes 256 times?


<Clown suit on>
Why didn't I buy a real C compiler...

<Clown suit off>